bootstrap: support checksum utils without a --status option * build-aux/bootstrap: Only look for sha1sum if updating po files. Add sha1 to the list of supported checksum utils since it's now supported through adjustments below. (update_po_files): Remove the use of --status in a way that will suppress all error messages, but since this is only used to minimize updates, it shouldn't cause an issue. Exit early if there is a problem updating the po file checksums. (find_tool): Remove the check for --version support as this is optional as per commit 86186b17. Don't even check for the presence of the command as if that is needed, it's supported through configuring prerequisites in bootstrap.conf. Prompt that when a tool isn't found, one can define an environment variable to add to the hardcoded search list.